Countertop oven with thin-film heating element

ABSTRACT

A cooking appliance includes an inner housing with an inner wall defining an interior space, an outer housing that includes an outer wall having an inner surface opposed to and spaced from an outer surface of the inner wall to define an insulating layer therebetween, and at least one thin-film heating element coupled to the outer surface of the inner wall.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 61/980,468 filed Apr. 16, 2014, which is incorporated herein in its entirety.

BACKGROUND

The present invention relates generally to cooking appliances used for baking foods, and more particularly to an oven capable of cooking different types of food products relatively quickly and properly.

Cooking appliances such as portable or tabletop cooking appliances including, e.g., pizza ovens and toaster ovens are used for baking various foods including, but not limited to, crusted-type foods, e.g., breads, pizzas, calzones, and the like. One drawback associated with at least some known cooking appliances is that they may be designed for only cooking a single type of food product. To cook a single type of food product, an oven may be designed to provide heat energy (e.g., infrared, convection, etc.) in a manner that facilitates optimizing cooking of that single type of food product, but that is inefficient and/or ineffective in cooking different types of food products.

For example, a cooking appliance may be designed to only cook a first type of food product (e.g., frozen pizza). Accordingly, if the same cooking appliance is used to cook a second type of food product (e.g., deep dish pizza), the second type of food product may be cooked improperly (e.g., unevenly heated, underheated, burned, soggy, etc.) in the cooking appliance.

Moreover, at least some known cooking appliances may have relatively long pre-heat times (e.g., 15 minutes or longer). This results in relatively long overall cook times, which are generally undesirable.

There is a need, therefore, for countertop cooking appliance that is capable of cooking different types of food products quickly and properly.

SUMMARY

In one embodiment, a cooking appliance generally comprises an inner housing enclosing an interior space, with the inner housing generally comprising an inner wall having an outer surface. An outer housing generally comprises an outer wall having an inner surface opposed to and spaced from the outer surface of the inner wall to define an insulating region therebetween. At least one thin-film heating element is coupled to the outer surface of the inner wall.

In another embodiment, a toaster oven generally comprises an outer housing enclosing an interior space, with the outer housing comprising a top wall defining an aperture passing therethrough. A thin-film heating element is situated within the aperture and coupled to the top wall. A panel is positioned over the thin-film heating element and spaced from the thin-film heating element to define an insulating region therebetween.

In yet another embodiment, a pizza oven generally comprises an inner housing enclosing an interior space, with the inner housing generally comprising a transparent inner top panel having an outer surface. An outer housing generally comprises a transparent outer top panel having an inner surface opposed to and spaced from the outer surface of the inner top panel to define an insulating region therebetween. A first thin-film heating element is coupled to the outer surface of the inner top panel.

BRIEF DESCRIPTION

FIG. 1 is a perspective view of a cooking appliance in accordance with one embodiment of the present disclosure;

FIG. 2 is a front view of the cooking appliance shown in FIG. 1 with the outer front panel removed to view the interior;

FIG. 3 is a perspective view of the cooking appliance shown in FIG. 1 with the outer door and inner door opened to view the interior;

FIG. 4 a perspective view of the cooking appliance shown in FIG. 1 with the outer door and inner door opened to view the interior;

FIG. 5 is a front view of the cooking appliance shown in FIG. 1 with the outer front panel removed to view the interior containing a food item;

FIG. 6 is a perspective view of a toaster oven in accordance with one embodiment of the present disclosure;

FIG. 7 is a perspective view of a pizza oven embodiment of the cooking appliance in accordance with one embodiment of the present disclosure; and

FIG. 8 is an exploded perspective view of a pizza oven embodiment shown in FIG. 7.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

With reference now to the drawings and in particular to FIGS. 1-5, a cooking appliance according to one embodiment of the present disclosure is generally indicated as 100. In this embodiment, the cooking appliance 100 is an oven for cooking food products, such as crusted foods (e.g., breads, pizzas, calzones, and the like). By way of non-limiting example, the cooking appliance 100 may be a pizza oven. In other embodiments, the cooking appliance 100 may be what is commonly referred to as a toaster oven. The cooking appliance 100 includes an outer housing 200 enclosing an inner housing (not shown) having an interior space 602 defined therein. To cook a food product 606, the food product 606 is placed within the interior space 602, as described herein.

Referring to FIGS. 1 and 2, the outer housing 200 includes an outer top 202, an outer bottom 208, an outer front 210, an outer back 212, and two outer sides 204/206. The outer back 212 and/or the outer sides 204/206 may include outer vents (not illustrated) for dissipating heat generated during operation of the cooking appliance 100. A set of outer legs 214 extend from the outer bottom 208 to support the outer housing 200 on a surface (e.g., a countertop, not illustrated). The outer housing 300 is configured to enclose the inner housing 200 and additionally an insulating region 220 situated between the outer housing 200 and the inner housing 300. The insulating region 220 may contain a non-electrically conductive and thermally insulating material surrounding the inner housing 300 to inhibit heat losses from the interior space 602 during use, to inhibit the heating of the outer housing 200, and to effectuate the function of the thin-film heating elements 400 and/or 500 as described herein below. In alternative embodiments, the insulating region 220 may be filled in whole or in part by a non-electrically conductive insulating material. Non-limiting examples of suitable insulating materials contained within the insulating region 220 include: air or other gas layers; a foam insulative material, a fibrous insulative material such as fiberglass, a shredded insulative material such as cellulose insulation, and any other known non-electrically conductive insulating material.

Referring again to FIGS. 1 and 2, the inner housing 300 includes an inner top 302, an inner bottom 308, an inner front 310, an inner back 312, and two inner sides 304/306. The inner back 312 and/or the outer sides 304/306 may include inner vents (not illustrated) for dissipating heat generated during operation of the cooking appliance 100.

Referring to FIG. 3, at least a portion of the outer front 210 may be pivotably coupled or hinged to an element of the outer housing 200 to facilitate access to the inner housing 300 of the cooking appliance 100, thereby functioning as an outer door 216. In this aspect, the outer door 216 is pivotable between an open position (as shown in FIG. 3) and a closed position (as shown in FIG. 1). In the open position, the inner housing 300 is exposed to facilitate inserting and removing a food product 606 from the interior space 602 within the inner housing 300 of the cooking appliance 100.

Referring again to FIG. 3, at least a portion of the inner front 310 may be pivotably coupled to an element of the inner housing 300 to facilitate access to the inner housing 300 of the cooking appliance 100, thereby functioning as an inner door 316. In this aspect, the inner door 316 is pivotable between an open position (as shown in FIG. 3) and a closed position (as shown in FIG. 1). In the open position, the inner housing 300 is exposed to facilitate inserting and removing a food product 606 from the interior space 602 within the inner housing 300 of the cooking appliance 100. In other embodiments, the inner door 316 and outer door 216 may be assembled together as a single unit for conjoint pivoting to open and close the cooking appliance 100.

During cooking, the inner door 316 and the outer door 216 are placed in the closed position to facilitate heating the interior space 602. Referring to FIG. 1, the outer door 216 may include an outer handle 218 to facilitate moving the door 216 between the open and closed positions during use. Similarly, the inner door 316 may include an inner handle 318 to facilitate moving the door 316 between the open and closed positions during use. In this embodiment, the outer door 216 is pivotably coupled proximate to one outer side 206 and the inner door 316 is pivotably coupled proximate to one inner side 206. Alternatively, the outer door 216 may be coupled proximate to another outer side 204, the outer bottom 208, and/or the outer top 202 using any suitable coupling mechanism that enables the outer door 216 to function as described herein. In addition, the inner door 316 alternatively may be coupled proximate to another inner side 304, the inner bottom 308, and/or the inner top 302 using any suitable coupling mechanism that enables the inner door 316 to function as described herein. In various embodiments, the outer door 216 and the inner door 316 may be hinged proximate to similar regions of the cooking appliance 100 including, but not limited to: the left front, as illustrated in FIG. 3, the top front, the bottom front, the right front, and any other suitable region of the cooking appliance 100 without limitation. In various other embodiments, the outer door 216 and inner door 316 may by hinged proximate to different regions of the of the cooking appliance 100. By way of non-limiting example, illustrated in FIG. 4, the outer door 216 may be hinged to the outer bottom 208 and the inner door 316 may be hinged to one inner side 306.

As shown in FIGS. 1-4, the food product 606 may be supported within the interior space 602 of the cooking appliance 100 by a bottom tray 604 resting on the bottom surface 320 defined by the inner bottom 308 of the inner housing 300. In other embodiments, as illustrated in FIG. 2, the food product 606 may be supported by one or more trays 612 affixed between the inner sides 304/306 of the inner housing 300. In these other embodiments, the cooking appliance 100 may further include one or more paired tray supports 608 affixed to the side surfaces 322 and 324 defined by the sides 304 and 306, respectively, of the inner housing 300, as illustrated in FIG. 2. Each pair of tray supports 608 defines a support means 610 for receiving a tray (not shown), as described in detail herein below. In various embodiments (not shown), the cooking appliance 100 may include two or more paired tray supports 608 to provide two or more support means 610 situated at two or more different heights above the bottom surface 320 within the interior space 602. Non-limiting examples of suitable tray support means 610 include a groove, a slot, a shelf, and the like.

In various embodiments, the cooking appliance 100 further includes at least one thin-film heating element. As used herein, a thin-film heating element refers to an electrically conductive material (e.g., a conductive film) deposited on a substrate for heating the substrate. The heating element is said to be a “thin-film” heating element in the sense that the substrate and the electrically conductive material have a collective thickness that is only marginally greater than the substrate itself (i.e., the material forms a thin film on the substrate).

The thin-film heating element may include, for example, a metal oxide (e.g., tin oxide) resistive film bounded on opposing edges by electrical bus bars. By applying a voltage between the bus bars, current flows through the resistive film, heating the resistive film and a substrate on which the resistive film is deposited. Using a thin-film heating element improves power efficiency, heating uniformity, and speed of heating. Further, the thinness and conductive heat directionality of a thin-film heating element also permit a cooking appliance to have a thinner profile. In various embodiments, thin-film heating elements may instead or additionally be applied to baking plates, cooking racks (e.g., metallic or glass racks), and/or any other heating surface.

Referring again to FIGS. 1 and 2, the cooking appliance 100 in one embodiment may include an upper thin-film heating element 400 and/or a lower thin-film heating element 500. The upper thin-film heating element 400 is coupled to the exposed outer surface 326 of the inner top 302, which serves as an electrically insulating substrate. In other embodiments (not shown) thin-film heating elements may be instead or additionally situated on the exposed outer surfaces of one or more of the sides of the inner housing 300 including, but not limited to, the inner top 302, the inner bottom 308, the inner front 310, the inner back 312 and/or the inner sides 304 and/or 306.

Referring to FIG. 2, the upper thin-film heating element 400 may be positioned between the outer top 202 of the outer housing 200 and the inner top 302 of the inner housing 300 with the insulating region 220 situated between the outer top 202 and the inner top 302, thereby forming an insulative air gap. Heat generated by the upper thin-film heating element 400 radiates downward, through the inner top 302. Notably, the heat generated by the upper thin-film heating element 400 is substantially unidirectional, and little to no heat generated by the upper thin-film heating element 400 is radiated upward, through the outer top 202. The outer top 202 also prevents a user from accidentally coming into contact with the thin-film heat element 400 during operation.

Similarly, the lower thin-film heating element 500 may be positioned between the outer bottom 208 of the outer housing 200 and the inner bottom 308 of the inner housing 300 with the insulating region 220 situated between the outer bottom 208 and the inner bottom 308, thereby forming an insulative air gap. Heat generated by the lower thin-film heating element 500 radiates upward, through the inner bottom 308. Notably, the heat generated by the lower thin-film heating element 500 is substantially unidirectional, and little to no heat generated by the lower thin-film heating element 500 is radiated downward, through the outer bottom 208. The outer bottom 208 also prevents a user or countertop from accidentally coming into contact with the thin-film heat element 500 during operation.

The upper thin-film heating element 400 includes an upper resistive film 402 extending between a first upper bus bar 404 and a second upper bus bar 406. The lower thin-film heating element 500 is coupled to the exposed surface 328 of the inner bottom 308, which serves as an electrically insulating substrate. The lower thin-film heating element 500 includes a lower resistive film 502 extending between a first lower bus bar 504 and a second lower bus bar 506.

In this embodiment, the resistive films 402 and 502 of the upper and lower thin-film heating elements 400 and 500 are sputter coated onto the respective exposed upper and lower surfaces 326 and 328. Thin-film heating elements 400 and 500 may each have an output power of approximately 1500 Watts.

The upper heating element 400 may have a maximum power output of, for example, up to 2200 Watts (W). For example, in one embodiment, the upper heating element 400 has a maximum power output of 450 W. Further, in some embodiments, the maximum power output may be more than 2200 W.

The lower heating element 500 may have a maximum power output of, for example, up to 2200 Watts (W). For example, in one embodiment, the lower heating element 500 has a maximum power output of 450 W. Further, in some embodiments, the maximum power output may be more than 2200 W.

The thin-film heating elements 400 and 500 may have a combined maximum power output of, for example, up to 2200 W. For example, in one embodiment, each of the thin-film heating elements 400 and 500 has a maximum power output of 750 W, for a combined output power of 1500 W. In some embodiments, at least some of the thin-film heating elements 400 and 500 have different maximum power outputs from each other. For example, the thin-film heating element 400 may have a higher maximum power output than the remaining upper heating elements 160.

In the embodiment shown, the thin-film heating elements 400 and 500 are substantially planar. Alternatively, the heating elements 400 and 500 may have any suitable shape. For example, ribs (i.e., substantially parallel bars) may be formed on the heating elements 400 and 500 to facilitate forming sear marks on cooked food products. Notably, in this embodiment, the lower thin-film heating element 500 and inner bottom 308 form a non-scratch surface. Accordingly, once a food product is cooked using the cooking appliance 100, the food product may be cut while resting on the inner bottom 308.

Notably, the thin-film heating elements 400 and 500 and associated substrates (inner top 302 and inner bottom 308) may be substantially transparent. At least a portion of the remaining outer housing 200 and inner housing 300 may be substantially transparent. Accordingly, as seen in FIGS. 1-4, during cooking, a user may view the food product inside of the cooking appliance 100 by looking through the essentially transparent portions of the inner and outer housings 200 and 300. This allows a user to view the food product without needing to open the cooking appliance 100, which would generate in a loss of heat within the cooking appliance 100.

Because of the thin-film heating elements 400 and/or 500, the cooking appliance 100 may heat up faster than at least some known cooking appliances, and may also provide improved thermal recovery and temperature stabilization. Further, the thin-film heating elements 400 and 500 cook food products using a combination of infrared and conduction cooking. Moreover, because the food product cooked within the cooking appliance 100 is not squeezed between the lower heating element 500 and the upper heating element 400, the food product may retain more moisture during cooking as opposed to if the food product was cooked in at least some known cooking appliances. The cooking appliance 100 may be powered using direct current (DC) power or alternating current (AC) power.

In an additional embodiment, illustrated in FIG. 6, the cooking appliance 100 may be a toaster oven 100A. FIG. 6 is a perspective view of one embodiment of a toaster oven 100A that includes one or more thin-film heating elements 1002. The toaster oven 100A includes a housing 200 defining an interior space 1024. The housing 200 includes a top wall 1004, a bottom wall 1006, two opposing side walls 1008, and a back wall 1010. A plurality of legs 1012 extend downward from the bottom wall 1006.

As shown in FIG. 6, the top wall 1004 includes an aperture 1014 defined therethrough. The thin-film heating element 1002 is sized to fit in the aperture 1014 and couple to the top wall 1004. In some embodiments, aperture 1014 may be defined by a ledge (not shown) that supports the thin-film heating element 1002.

In this embodiment, the thin-film heating element 1002 includes a resistive film 1020 applied to a substantially transparent substrate 1022 (e.g., ceramic glass). Running a current through resistive film 1020 causes heat to be emitted downward through the substrate 1022 into an interior space 1024 where a food product (not shown) is located.

To prevent a user from contacting the heating element 1002 during operation of the toaster oven 100A, a substantially transparent panel 1030 is positioned above the thin-film heating element 1002 and separated from the thin-film heating element 1002 by an insulating region 220 (not shown). The panel 1030 may be, for example, ceramic glass. Because the thin-film heating element 1002 and the panel 1030 are substantially transparent, the user can view the food product from above during cooking.

To insert and remove the food product from the toaster oven 100A, a door 1040 is rotatably coupled at least one of the bottom wall 1006 and the side walls 1008. In this embodiment, the door 1040 includes a handle 1042 and a substantially transparent window 1044 that allows the user to view the food product during cooking. The toaster oven 100A includes vents 1046 to facilitate cooling the toaster oven 100A, and includes one or more control knobs 1048 to allow the user to control operation of the toaster oven.

In this embodiment, the side walls 1008 do not include heating elements. Alternatively, at least one of the side walls 1008 may include a heating element and transparent panel, such as the thin-film heating element 1002 and the panel 1030. Accordingly, in such embodiments, at least a portion of the side walls 1008 may be substantially transparent. In other embodiments, the side walls 1008 may include a transparent panel, such as the panel 1030, without including a heating element.

In an additional embodiment, illustrated in FIGS. 7 and 8, the cooking appliance 100 may be a pizza oven 100B. The pizza oven 100B may include an outer housing 200 enclosing an inner housing 300 having an interior space 602 defined therein. In this embodiment, the outer housing 200 may include an outer top 202 in which a transparent outer top panel 203 is inset. The inner top 302 similarly includes a transparent inner top panel 303 situated directly beneath the transparent outer top panel 203 and separated from the transparent inner top panel 303 by an insulating region 220. An upper thin-film heating element 400 similar to the upper thin-film heating element 400 described herein previously is coupled to the transparent inner top panel 303 on the outer surface 326 facing the overlying transparent outer top panel 203. In this embodiment, the upper thin-film heating element 400 includes an upper resistive film 402 extending between a first upper bus bar 404 and a second upper bus bar 406.

Referring again to FIGS. 7 and 8, a lower heating element 500 may be situated at the inner bottom 308 to generate heat from below into the interior space 602. In one embodiment, the lower heating element 500 may be any known suitable heating element including, but not limited to: a quartz-type heating element, a ceramic-type heating element, a halogen-type heating element, a calrod-type heating element, a thin-film heating element 500, and any combination thereof. In one embodiment, the lower heating element 500 may be a thin-film heating element coupled to the inner bottom 308 as described herein previously. In another embodiment, the lower heating element 500 may be a thin-film heating element coupled to the inner bottom 308 in combination with one other heating element situated at the bottom of the interior space 602. In this other embodiment the one other heating element may be selected from a quartz-type heating element, a ceramic-type heating element, a halogen-type heating element, or a calrod-type heating element.

Referring again to FIGS. 7 and 8, the outer front 210 may include a rack front face 209 and a pan front face 211 that fit against a front opening 213 to form a continuous outer front 210 and a continuous inner front 310 (not shown) when the rack 616 and pan 614 of the tray 612 are inserted into the interior space 602. The inserted pan 614 and the tray 612 may be supported by the support means 610 defined within each pair of tray supports 608 attached to the inner side surfaces 322 and 324. In one embodiment, the rack front face 209 and pan front face 211 may include an attached rack handle 215 and tray handle 217, respectively, to facilitate the insertion and removal of the rack 616 and pan 614 of the tray 612 in and out of the interior space 602, and to provide relatively cool regions for grasping by the user during use.

With reference back to FIG. 3, any of the cooking appliances 100, 100A, 100B described herein may include one or more input devices 600 including, but not limited to a mode selection knob 602 and a timer knob 604. The mode selection knob 602 and timer knob 604 shown in FIG. 3 are non-limiting examples of suitable input devices 600 for selecting a mode and setting a cook time. Alternative input devices 600 usable with the cooking appliance 100 may include, for example, slide switches, buttons, toggle switches, touch screens, user interfaces, and/or any other type of suitable input device. Further, in some embodiments, a user may select a mode and/or set a cooking time using a computing device (e.g., a tablet, a desktop computer, a laptop computer, a mobile phone, etc.) as the input device, where the computing devices communicates remotely with the oven over a wired and/or wireless network, such as the Internet, or any other communications medium (e.g., Bluetooth®). For example, the user may use a software application on a computing device that enables the user to input a selected mode and/or set a cooking time, where the input information is communicated from the computing device to the cooking appliance 100. Further, the cooking appliance 100 may communicate information to the computing device (e.g., remaining cook time) to notify the user.

In various embodiments, the one or more input devices may be located anywhere upon the outer housing 200 accessible to the user during use including, but not limited to the outer top 202, outer back 204, outer sides 204 (illustrated in FIG. 3) or 206, and/or outer front 210.

Referring again to FIG. 3, by rotating the mode selection knob 602, a user can select different modes of operation for the cooking appliance 100 based on the type of food product to be cooked. Specifically, the operations of the upper thin-film heating element (e.g. element 400 in FIG. 5) and the lower heating element (e.g. element 500 in FIG. 5) are modulated in a coordinated manner based on the selected mode, according to known modes of operation. For example, the cooking appliance 100 may include a broil mode, where the lower heating element (e.g. element 500 in FIG. 5) is off and the upper thin-film heating element (e.g. element 400 in FIG. 5) is on (i.e., either fully or partially on).

In this embodiment, a controller (e.g., a microcontroller), controls the operation of the upper thin-film heating element 400 and lower heating element 500 based on the mode selected using the mode selection knob 602. The cooking appliance 100 may also include an indicator 606 (e.g., an LED) that indicates when the cooking appliance 100 is on. At least one input device (e.g., the mode selection knob 602) enables a user to select a cooking mode from a plurality of selectable cooking modes for the cooking appliance 100. Each of the selectable modes may correspond to, for example, cooking a different type of food product. Those of skill in the art will appreciate that the cooking appliance 100 may include any suitable number of selectable modes.

Each mode includes an associated set of operating parameters. These operating parameters are designed to facilitate optimizing the cooking of a particular type of food product (i.e., the type of food product corresponding to the mode having the associated operating parameters). Although specific modes and associated operating parameters are described herein, those of skill in the art will appreciate that the cooking appliance 100 may include other modes and/or other operating parameters than those specifically described herein.

Referring back to FIG. 2, the inner housing 300 includes a means 610 configured to receive a substantially planar tray 612. The means 610 may include, for example, a slot, a shelf, a groove, and/or other structure for receiving the tray 612.

FIG. 2 further shows a bottom tray 604 standing on the bottom 320 within the interior space 602 of the cooking appliance 100. The bottom tray 604 may catch crumbs, grease, fat, and the like that drops from the food product during cooking. In addition, the bottom tray 604 may provide support to larger food items during cooking. Further, the bottom tray 302 is removable from the cooking appliance 100 for easy disposal of the contents of the bottom tray 604. The bottom tray 604 or the inner bottom 308 of the inner housing 300 may form the bottom surface 320 within the interior space 602.

As described above, the means 610 receive a tray 612. FIG. 2 shows a tray 612 fully inserted into the cooking appliance 100. The tray 612 supports the food product during cooking and facilitates uniform heating of the food product, as described herein. The tray 612 may be any known essentially planar support structure suitable for use in a cooking appliance 100 including, but not limited to: a tray, a sheet, a rack, a pan, a grill, and any other suitable essentially planar support structure.

In one embodiment, the tray 612 may be metallic (e.g., aluminum, steel, and the like). Alternatively, the tray 612 may be made of any suitable thermally conductive material. For example, in some embodiments, the tray 612 may be aluminum, steel, copper, ceramic, or glass. The tray 612 should both be resistant to relatively high temperatures. Further, the tray 612 should have a sufficiently rigid structure and structural integrity to support the food item.

As compared to at least some known cooking appliances, the cooking appliances described herein cook a food product more quickly, and more uniformly. The thin-film heating elements within the cooking appliances described herein enable more rapid heating of the interior space and quicker adjustments of the cooking temperature during use. In addition, the thin footprint of the thin-film heating elements within the cooking appliances described herein enable a more compact overall size compared to other known cooking appliances. Further, the inclusion of thin-film heating elements enable the use of essentially transparent walls to form the cooking appliance described herein, thereby providing enhanced visual inspection and/or monitoring of the food product during cooking.

The cooking appliances described herein provide multiple heating modes for cooking different types of food products (e.g., different types of pizza). By selecting a mode that corresponds to a type of food product to be cooked, the cooking appliances described herein are able to adjust upper and lower heating elements to facilitate improved cooking of that type of food product. By using different modes for different food product (e.g., by controlling upper and lower thin-film heating elements independently), the amount of heat energy emitted to the food product can be controlled, improving cooking results. That is, in the embodiments described herein, the cooking mode of the cooking appliance can be modified to address differences in the type of food product being cooked by changing the configuration of energy (e.g., convection, infrared, etc.) being delivered to the food product.

Moreover, by controlling energy delivery to a food product as described herein, the cooking appliances disclosed have substantially reduced pre-heat times, relative to at least some known cooking appliances. Accordingly, unlike at least some known cooking appliances, the systems and methods described herein enable cooking different types of food products efficiently and properly using the same cooking appliance.

When introducing elements of the present invention or the preferred embodiment(s) thereof, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 

What is claimed is:
 1. A cooking appliance comprising: an inner housing enclosing an interior space, the inner housing comprising an inner wall having an outer surface; an outer housing comprising an outer wall having an inner surface opposed to and spaced from the outer surface of the inner wall to define an insulating region therebetween; and at least one thin-film heating element coupled to the outer surface of the inner wall.
 2. The cooking appliance of claim 1, wherein each of the at least one thin-film heating elements comprises a resistive film extending between a pair of electrical bus bars.
 3. The cooking appliance of claim 2 wherein the resistive film is coupled to the outer surface of the inner wall.
 4. The cooking appliance of claim 2 wherein the first resistive film comprises a metal oxide.
 5. The cooking appliance of claim 4 wherein the metal oxide comprises tin oxide.
 6. The cooking appliance of claim 1, wherein the inner wall is constructed of at least one of: ceramic, clay, stone, glass, concrete, brick, and porcelain.
 7. The cooking appliance of claim 1, wherein the inner wall comprises a substantially transparent material.
 8. The cooking appliance of claim 1, wherein the outer housing comprises a substantially transparent material.
 9. The cooking appliance of claim 1, wherein the at least one thin-film heating element comprises an upper thin-film heating element situated on a top portion of the inner housing.
 10. The cooking appliance of claim 9, wherein the at least one thin-film heating element further comprises a lower thin-film heating element situated on a bottom portion of the inner housing.
 11. The cooking appliance of claim 10, further comprising a controller configured to operate the at least one thin-film heating element in accordance with a selected mode of a plurality of selectable modes, wherein operating parameters for the at least one thin-film heating element varies between the plurality of selectable modes, the selectable modes comprising modulation of the upper thin-film heating element and the lower thin-film heating element to maintain a predetermined temperature in the interior space.
 12. A toaster oven comprising: an outer housing enclosing an interior space, the outer housing comprising a top wall defining an aperture passing therethrough; a thin-film heating element situated within the aperture and coupled to the top wall; a panel positioned over the thin-film heating element and spaced from the thin-film heating element to define an insulating region therebetween.
 13. The toaster oven of claim 12, wherein the thin-film heating element comprises a resistive film coupled to an outer surface of an electrically non-conductive substrate, the resistive film extending between a pair of electrical bus bars.
 14. The toaster oven of claim 13 wherein the resistive film comprises a metal oxide.
 15. The toaster oven of claim 14 wherein the metal oxide comprises tin oxide.
 16. The toaster oven of claim 13, wherein the electrically non-conductive substrate and the panel comprise a substantially transparent material.
 17. A pizza oven comprising: an inner housing enclosing an interior space, the inner housing comprising a transparent inner top panel having an outer surface; an outer housing comprising a transparent outer top panel having an inner surface opposed to and spaced from the outer surface of the inner top panel to define an insulating region therebetween; and a first thin-film heating element coupled to the outer surface of the inner top panel.
 18. The pizza oven of claim 17, wherein the thin-film heating element comprises a resistive film extending between a pair of electrical bus bars.
 19. The pizza oven of claim 18, wherein the resistive film is coupled to the outer surface of the inner wall.
 20. The pizza oven of claim 17, further comprising a lower heating element situated on a bottom portion of the inner housing. 